Improve DEFINE_STATIC_LOCAL()'s handling of Blink GCed objects.

third_party/WebKit/Source/core/dom/custom/CustomElementMicrotaskDispatcher.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/custom/CustomElementMicrotaskDispatcher.h"
 
 #include "bindings/core/v8/Microtask.h"
 #include "core/dom/custom/CustomElementCallbackQueue.h"
 #include "core/dom/custom/CustomElementMicrotaskImportStep.h"
 #include "core/dom/custom/CustomElementProcessingStack.h"
 #include "core/dom/custom/CustomElementScheduler.h"
 
 namespace blink {
 
 static const CustomElementCallbackQueue::ElementQueueId kMicrotaskQueueId = 0;
 
 CustomElementMicrotaskDispatcher::CustomElementMicrotaskDispatcher()
     : m_hasScheduledMicrotask(false)
     , m_phase(Quiescent)
 {
 }
 
 CustomElementMicrotaskDispatcher& CustomElementMicrotaskDispatcher::instance()
 {
-    DEFINE_STATIC_LOCAL(Persistent<CustomElementMicrotaskDispatcher>, instance, (new CustomElementMicrotaskDispatcher()));
-    return *instance;
+    DEFINE_STATIC_LOCAL(CustomElementMicrotaskDispatcher, instance, (new CustomElementMicrotaskDispatcher));
+    return instance;
 }
 
 void CustomElementMicrotaskDispatcher::enqueue(CustomElementCallbackQueue* queue)
 {
     ensureMicrotaskScheduledForElementQueue();
     queue->setOwner(kMicrotaskQueueId);
     m_elements.append(queue);
 }
 
 void CustomElementMicrotaskDispatcher::ensureMicrotaskScheduledForElementQueue()
@@ skipping 42 matching lines @@
 }
 
 DEFINE_TRACE(CustomElementMicrotaskDispatcher)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_elements);
 #endif
 }
 
 } // namespace blink